Can you stay up late to see an eclipse?

The different stages of the moon during a lunar eclipse are seen from the Griffith Observatory in Los Angeles. On Tuesday morning, April 15, 2014, the moon will be eclipsed by Earth's shadow and will be visible across the Western Hemisphere. The total phase will last 78 minutes. (AP Photo/Ringo H.W. Chiu)

The different stages of the moon during a lunar eclipse are seen from the Griffith Observatory in Los Angeles. On Tuesday morning, April 15, 2014, the moon will be eclipsed by Earth’s shadow and will be visible across the Western Hemisphere. The total phase will last 78 minutes. (AP Photo/Ringo H.W. Chiu)

Hey, kids of North and South America, get ready for the first eclipse of the year, but you’ll have to get up really early or stay up really late.

Next Tuesday morning (April 15), the moon will be eclipsed by Earth’s shadow. This total lunar eclipse will be visible across the Western Hemisphere, which includes all of North America. The total shadowed phase will last 78 minutes, beginning at 3:06 a.m. and ending at 4:24 a.m..

Even though the moon is in the Earth’s shadow, it should appear a bit colorful, some shade of red or orange. That’s from light around the edges of the Earth — essentially sunrises and sunsets — splashing on the lunar surface and faintly lighting up the moon, said Alan MacRobert, senior editor at Sky & Telescope magazine.

On April 29, the Southern Hemisphere will be treated to a rare type of solar eclipse.

In all, four eclipses will occur this year, two lunar and two solar.

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Online:

NASA: http://1.usa.gov/NFJLGE

Reported by MARCIA DUNN of the Associated Press from CAPE CANAVERAL, Fla.

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Catch up with the world’s satellites

This NOAA satellite image taken Wednesday, March 26, 2014 at 10:45 AM  shows a prominent storm wound up off the the Northeast US with clouds across much of the western Atlantic Basin with heavy snow and strong winds affecting Nova Scotia and coastal New England.  (AP PHOTO/WEATHER UNDERGROUND)

This NOAA satellite image taken Wednesday, March 26, 2014 at 10:45 AM shows a prominent storm wound up off the the Northeast US with clouds across much of the western Atlantic Basin with heavy snow and strong winds affecting Nova Scotia and coastal New England. (AP PHOTO/WEATHER UNDERGROUND)

The use of satellites during the search for a lost jetliner has drawn attention to those orbiting platforms. Here is a snapshot of what’s in orbit, with help from Nicholas Johnson, who retired Thursday as NASA’s chief scientist for orbital debris:

HOW MANY SATELLITES ARE UP THERE?

About 1,100 active satellites, both government and private. Plus there are about 2,600 ones that no longer work. Russia launched the first satellite, Sputnik 1, in 1957. The oldest one still in orbit, which is no longer functioning, was launched in 1958.

HOW BIG ARE THEY?

Size varies. Communication satellites can be as big as a small school bus and weigh up to 6 tons, the Federal Communications Commission says. Most weigh a few tons or less. Some that are used briefly are 4 inch cubes and weigh about 2 pounds.

WHAT EXACTLY DO THEY DO?

They have a wide variety of roles: GPS satellites aid navigation, others relay telephone or television signals, others aid in weather forecasting, national defense, science, and agriculture, as in monitoring crops and areas of drought. The Union of Concerned Scientists, a private organization that maintains a database of satellites, says about 60 percent are used for communications.

WHERE ARE THEY?

It depends on their use. Communications satellites relay signals from a fixed spot on the equator, about 22,000 miles up. GPS satellites are at 12,400 miles, high enough to be accessible to large swaths of the Earth. Others that need a closer look at Earth are lower. For comparison, the International Space Station is only about 260 miles high, and very few satellites are lower than that. While some satellites remain over fixed spots on Earth, others fly over both poles or can move from place to place as needed.

You can see their locations at the NASA satellite tracker: http://1.usa.gov/1dyKhCd

HOW HAVE THEY HELPED IN THE SEARCH?

A British communications satellite picked up signals from the plane; analysis of them led authorities to conclude that the airliner crashed in a remote area of the southern Indian Ocean. This week, Thai authorities said one of their satellites spotted 300 objects that might be from the airliner. Some satellites were moved into place to look for debris.

WHO OWNS THEM?

Governments large and small, and private companies. More than 50 countries own a satellite or a significant share in one, according to the Union of Concerned Scientists. There are 502 active satellites with a U.S. tie; 118 for Russia and 116 for China. Thailand has four satellites and shares in another, the scientist group says.

WHAT IF THEY STOP WORKING?

Old satellites can pose a risk for collisions with active ones, so there are rules and recommendations to avoid a buildup of junk in space. Satellites that fly below a certain height are supposed to be put in an orbit that will make them fall to Earth and burn up within 25 years. At high altitudes, they are to be boosted up to still higher orbits to get them out of the way.

Reported by MALCOLM RITTER of the Associated Press

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Detecting distant planets with the Doppler Effect

This artist's conception  shows a hypothetical planet with two moons orbiting in the habitable zone of a red dwarf star. (AP Photo/Harvard-Smithsonian Center for Astrophysics, David A. Aguilar)

This artist’s conception shows a hypothetical planet in our galaxy. Scientists are using the Doppler effect to detect new planets. (AP Photo/Harvard-Smithsonian Center for Astrophysics, David A. Aguilar)

An ambulance whizzes by, and suddenly its siren drops in pitch. We are all familiar with the Doppler effect, even if we don’t know it by name. Now, scientists have found an alternative version of the phenomenon, for when sound, or light, scatters off a rotating object. The discovery could enable astronomers to measure a distant planet’s rotation, or even improve the performance of wind turbines.

Here’s how the Doppler effect works: When a noisy object is moving toward you, its sound waves bunch up, producing a higher frequency, or pitch. Conversely, as soon as the object is moving away from you, the sound waves stretch out, and the pitch lowers. The faster the object, the greater the pitch change.

The Doppler effect occurs for light as well as sound. For instance, astronomers routinely determine how fast stars and galaxies are moving away from us by measuring the extent to which their light is “stretched” into the lower frequency, red part of the spectrum. Redshifts like this were famously used in the 1920s to infer that most stars and galaxies are moving away from us and that the universe must be expanding.

Redshifts in light, and the pitch-drop of passing sirens, are examples of a linear Doppler effect. In recent decades, however, scientists have discovered that the Doppler effect also exists for objects that are rotating,  the so-called orbital angular momentum (OAM) of light, and now researchers they believe they can determine how fast a planet is spinning.

Back on Earth, he adds, lasers that measure the OAM could be sent through wind farms to determine the rotation of air currents. “If you’re a windmill, you’d like to know in advance of blustery wind, so you can tether your blades.”

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Reported by JON CARTWRIGHT of ScienceNOW. This is adapted from ScienceNOW, the online daily news service of the journal Science. http://news.sciencemag.org

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Saturn churns out a monster hurricane

 NASA's Cassini spacecraft snapped this stunning view of a monster hurricane at Saturn's North Pole. (AP Photo/NASA/JPL-Caltech/SSI)

NASA’s Cassini spacecraft snapped this stunning view of a monster hurricane at Saturn’s North Pole. (AP Photo/NASA/JPL-Caltech/SSI)

NASA’s Cassini spacecraft has captured stunning views of a monster hurricane at Saturn’s North Pole.

The eye of the cyclone is an enormous 1,250 miles across. That’s 20 times larger than the typical eye of a hurricane here on Earth. And it’s spinning super-fast. Clouds at the outer edge of the storm are whipping around at 330 mph.

The hurricane is parked at Saturn’s North Pole and relies on water vapor to keep it churning. It’s believed to have been there for years. Cassini only recently had a chance to observe the vortex in visible light.

Scientists hope to learn more about Earth’s hurricanes by studying this whopper at Saturn.

Cassini was launched from Cape Canaveral in 1997 and arrived at Saturn in 2004.

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Online:

NASA: http://saturn.jpl.nasa.gov/

Reported by MARCIA DUNN of the Associated Press from CAPE CANAVERAL, Fla.

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‘The best planets’ yet

Alien Planets

An international team of astronomers has found two planets whose size and position suggest they may support alien life.

The planets orbit a star about 2,000 light-years away from Earth. The star is named Kepler-62. The planets appear to be the right distance from their star for liquid water. With the chance of water, there’s also a chance for life to exist, according to research published online Thursday by the journal Science.

Compared with Earth, the planets, named Kepler-62e and Kepler-62f, are larger and receive 0.41 and 1.2 times the amount of solar radiation. The planet hunters, led by NASA’s William Borucki, say they won’t know what the planets look like or if they are in fact habitable until they can study them a while longer.

“We have found two planets in the habitable zone of another star, and they are the best planets found to date” that may support life, said Borucki, a space scientist at NASA’s Ames Research Center in Moffett Field, Calif.

One of the planets, Kepler-62f, may be a rocky celestial body with polar ice caps, Borucki said. The other, Kepler-62e, is believed to be warm and have lightning. While it’s too soon to know for sure, it may even be a water world, the first of its kind discovered, Borucki said.

“Kepler-62e probably has a very cloudy sky and is warm and humid all the way to the polar regions,” Dimitar Sasselov, an astronomer at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., said. “Kepler-62f would be cooler, but still potentially life-friendly.”

Mission accomplished: The planets were discovered using NASA’s Kepler satellite, a spacecraft launched in 2009 with a mission to discover Earth-size and smaller celestial bodies in regions around their stars, particularly those where liquid water may exist. The spacecraft was launched in March 2009 and has found more than 2,700 planet candidates.

Kepler detects planets that cross the face of their stars, and gathers data that enables astronomers to estimate the sizes and make suggestions about composition.

The Kepler planets have 1.41 and 1.61 the radius of the Earth, according the researchers. Both planets may be solid, with either rocky or icy compositions, the scientists said.

In 2011, the Kepler mission found its first planet in the habitable zone, called Kepler-22b. That planet is larger than Earth, and orbits a sun-like star every 290 days.

Reported by EVA VON SCHAPER and ELIZABETH LOPATTO for Bloomberg News.

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